Abstract

The vibrational and structural properties of a hydrogen-rich group IVa hydride, Sn(CH3)4, have been investigated by combining Raman spectroscopy and synchrotron x-ray diffraction measurements at room temperature and at pressures up to 49.9 GPa. Both techniques allow the obtaining of complementary information on the high-pressure behaviors and yield consistent phase transitions at 0.9 GPa for the liquid to solid and 2.8, 10.4, 20.4, and 32.6 GPa for the solid to solid. The foregoing solid phases are identified to have the orthorhombic, tetragonal, monoclinic crystal structures with space groups of Pmmm for phase I, P4/mmm for phase II, P2/m for phase III, respectively. The phases IV and V coexist with phase III, resulting in complex analysis on the possible structures. These transitions suggest the variation in the inter- and intra-molecular bonding of this compound.

Received 25 September 2012Accepted 17 December 2012Published online 10 January 2013

Acknowledgments:

X.J.C. and H.K.M. acknowledge EFree, an Energy Frontier Research Center funded by DOE-BES under Grant No. DE-SC0001057 for the structure measurements. The Raman measurements and theoretical calculations in China were supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project Ministry of Education of China (No. 708070), the Shenzhen Basic Research Grant (No. JC201105190880A), the National Natural Science Foundation of China (No. 11274335), Guangdong Natural Science Foundation (No. S2012040007929), and the Fundamental Research Funds for the Central Universities SCUT (No. 2012zz0078). The use of HPCAT, APS is supported by Carnegie Institution of Washington, Carnegie DOE Alliance Center, University of Nevada at Las Vegas, and Lawrence Livermore National Laboratory through funding from DOE–National Nuclear Security Administration, DOE–Basic Energy Sciences, and NSF. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357.